Postage stamps and tickets are produced in sheets having multiple stamps or tickets. The stamps or tickets have a self-stick adhesive applied to one side thereof and are adhered to a backing material which has a release surface on one side of it. The stamps or tickets can be individually removed from the backing sheet and placed on an envelope or other surface. However, if there is a large number of stamps or tickets arranged in a grid on a backing material, it is difficult to separate the stamps from each other on an individual or group basis so that the stamps can be subsequently removed from the backing material for application to an envelope or other surface. Thus, if a grid of fifty stamps, having five stamps to a row and ten stamps to a column, were provided, and it was desired to separate the stamps into two groups prior to using them, it would be extremely difficut if not impossible, to cut the underlying backing sheet with scissors to sever the stamps individually or into groups, especially when the stamps have contoured edges that simulate round hole perforations as is the case with conventional postage stamps.
The aforementioned sheets of stamps or tickets are manufactured by placing a sheet of printed material having a substantially uniform thickness and having a layer of self-stick adhesive applied to a side thereof, onto a sheet of backing material having a release surface on one side thereof. The backing material and the printed material are placed between an anvil and a knife to cut the sheet of printed material to a predetermined and constant depth so that the stamps or tickets are individually removable. However, because the underlying backing material is not cut, the stamps or tickets can not be separated individually or in groups prior to removal from the backing material.
Another method used to manufacture sheets of tickets or stamps is to perforate a sheet having a single thickness. When a group of stamps, tickets or other shapes are perforated in a single sheet of paper, the perforations are made by removing tiny cylindrical segments of paper material, thus leaving a line of holes in the paper. The paper may then be torn along the line of holes, thus separating the stamps or tickets individually. In the case of stamps, the stamps are then wetted and applied to an envelope. It would be desirable to provide a way of separating stamps or tickets from a sheet of paper without providing visible perforation holes along the perforation line.
Thus, it would be desirable to perforate the sheet of backing material so that individual self-adhesive stamps or tickets could be separated either individually or in groups from the other stamps or tickets, so that they may then be subsequently removed from the backing material and applied to an envelope or other surface.
Cutting devices which either cut completely through or perforate a sheet or web material are known in the art and include a variety of features to keep the cut items attached to the web material until a later stage in the processing or to merely weaken the material in locations to be later torn or folded along the weakened edge.
U.S. Pat. No. 3,138,985 to Mills discloses perforating plastic films with a non-continuous knife edge situated in a non-moving anvil portion. The plastic film is advanced in sections and a roller advances over the plastic film to cut two holes in the film at each end of the knife edge. The knife edge weakens the material in the area directly over the knife edge to control the direction that the film severs between the two holes, thus, creating a perforation in the plastic film.
U.S. Pat. No. 3,611,500 to Carrigan et al. discloses a machine that molds and cuts shapes out of a web sheet material. A knife both seals and cuts the edges of the desired shape. Recesses in an anvil allow sections along the shape's edge to be compressed into a tab which holds the formed article in the web sheet matrix until a later point in the processing.
U.S. Pat. No. 4,934,231 to Chesnut et al. discloses a rotary die-cutting device which uses two rollers to cut shapes from a sheet material. The device both cuts desired edges in the material and weakens the material in desired location to facilitate folding of the cut out shape.
None of the prior art devices teach cutting through only a portion of the sheet material while simultaneously perforating through the entire thickness of the sheet material.
What is desired, therefore, is an apparatus for cutting sheet material which cuts a portion of the way through the thickness of the material in a continuous cut while simultaneously perforating the material with a continuous cutting edge having its entire tip portion contained in the same plane.